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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-21 16:28:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-21 16:28:25 -0800
commit5d4740fc787db767811c4ac625665493314b382c (patch)
treed71092250b0b4905d794050593465559eb0ada8a
parent0a924817d2ed9396401e0557c6134276d2e26382 (diff)
parent5ad70eb27d2b87ec722fedd23638354be37ea0b0 (diff)
downloadlwn-5d4740fc787db767811c4ac625665493314b382c.tar.gz
lwn-5d4740fc787db767811c4ac625665493314b382c.zip
Merge tag 'io_uring-6.2-2022-12-19' of git://git.kernel.dk/linux
Pull io_uring fixes from Jens Axboe: - Improve the locking for timeouts. This was originally queued up for the initial pull, but I messed up and it got missed. (Pavel) - Fix an issue with running task_work from the wait path, causing some inefficiencies (me) - Add a clear of ->free_iov upfront in the 32-bit compat data importing, so we ensure that it's always sane at completion time (me) - Use call_rcu_hurry() for the eventfd signaling (Dylan) - Ordering fix for multishot recv completions (Pavel) - Add the io_uring trace header to the MAINTAINERS entry (Ammar) * tag 'io_uring-6.2-2022-12-19' of git://git.kernel.dk/linux: MAINTAINERS: io_uring: Add include/trace/events/io_uring.h io_uring/net: fix cleanup after recycle io_uring/net: ensure compat import handlers clear free_iov io_uring: include task_work run after scheduling in wait for events io_uring: don't use TIF_NOTIFY_SIGNAL to test for availability of task_work io_uring: use call_rcu_hurry if signaling an eventfd io_uring: fix overflow handling regression io_uring: ease timeout flush locking requirements io_uring: revise completion_lock locking io_uring: protect cq_timeouts with timeout_lock
-rw-r--r--MAINTAINERS1
-rw-r--r--io_uring/io_uring.c40
-rw-r--r--io_uring/io_uring.h14
-rw-r--r--io_uring/net.c3
-rw-r--r--io_uring/rw.c2
-rw-r--r--io_uring/timeout.c14
6 files changed, 44 insertions, 30 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index b701de08d602..f61eb221415b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10878,6 +10878,7 @@ T: git git://git.kernel.dk/liburing
F: io_uring/
F: include/linux/io_uring.h
F: include/linux/io_uring_types.h
+F: include/trace/events/io_uring.h
F: include/uapi/linux/io_uring.h
F: tools/io_uring/
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index b521186efa5c..ff2bbac1a10f 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -538,7 +538,7 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx)
} else {
atomic_inc(&ev_fd->refs);
if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
- call_rcu(&ev_fd->rcu, io_eventfd_ops);
+ call_rcu_hurry(&ev_fd->rcu, io_eventfd_ops);
else
atomic_dec(&ev_fd->refs);
}
@@ -572,12 +572,11 @@ static void io_eventfd_flush_signal(struct io_ring_ctx *ctx)
void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
{
- if (ctx->off_timeout_used || ctx->drain_active) {
+ if (ctx->off_timeout_used)
+ io_flush_timeouts(ctx);
+ if (ctx->drain_active) {
spin_lock(&ctx->completion_lock);
- if (ctx->off_timeout_used)
- io_flush_timeouts(ctx);
- if (ctx->drain_active)
- io_queue_deferred(ctx);
+ io_queue_deferred(ctx);
spin_unlock(&ctx->completion_lock);
}
if (ctx->has_evfd)
@@ -597,6 +596,18 @@ static inline void __io_cq_unlock(struct io_ring_ctx *ctx)
spin_unlock(&ctx->completion_lock);
}
+static inline void io_cq_lock(struct io_ring_ctx *ctx)
+ __acquires(ctx->completion_lock)
+{
+ spin_lock(&ctx->completion_lock);
+}
+
+static inline void io_cq_unlock(struct io_ring_ctx *ctx)
+ __releases(ctx->completion_lock)
+{
+ spin_unlock(&ctx->completion_lock);
+}
+
/* keep it inlined for io_submit_flush_completions() */
static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
__releases(ctx->completion_lock)
@@ -916,7 +927,7 @@ static void __io_req_complete_post(struct io_kiocb *req)
io_cq_lock(ctx);
if (!(req->flags & REQ_F_CQE_SKIP))
- __io_fill_cqe_req(ctx, req);
+ io_fill_cqe_req(ctx, req);
/*
* If we're the last reference to this request, add to our locked
@@ -1074,9 +1085,9 @@ static void __io_req_find_next_prep(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
- io_cq_lock(ctx);
+ spin_lock(&ctx->completion_lock);
io_disarm_next(req);
- io_cq_unlock_post(ctx);
+ spin_unlock(&ctx->completion_lock);
}
static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
@@ -2470,7 +2481,14 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
}
if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS))
return -ETIME;
- return 1;
+
+ /*
+ * Run task_work after scheduling. If we got woken because of
+ * task_work being processed, run it now rather than let the caller
+ * do another wait loop.
+ */
+ ret = io_run_task_work_sig(ctx);
+ return ret < 0 ? ret : 1;
}
/*
@@ -2535,6 +2553,8 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
TASK_INTERRUPTIBLE);
ret = io_cqring_wait_schedule(ctx, &iowq, timeout);
+ if (__io_cqring_events_user(ctx) >= min_events)
+ break;
cond_resched();
} while (ret > 0);
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 1b2f0b2cc888..e9f0d41ebb99 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -87,17 +87,6 @@ static inline void io_req_task_work_add(struct io_kiocb *req)
#define io_for_each_link(pos, head) \
for (pos = (head); pos; pos = pos->link)
-static inline void io_cq_lock(struct io_ring_ctx *ctx)
- __acquires(ctx->completion_lock)
-{
- spin_lock(&ctx->completion_lock);
-}
-
-static inline void io_cq_unlock(struct io_ring_ctx *ctx)
-{
- spin_unlock(&ctx->completion_lock);
-}
-
void io_cq_unlock_post(struct io_ring_ctx *ctx);
static inline struct io_uring_cqe *io_get_cqe_overflow(struct io_ring_ctx *ctx,
@@ -277,8 +266,7 @@ static inline int io_run_task_work(void)
static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
{
- return test_thread_flag(TIF_NOTIFY_SIGNAL) ||
- !wq_list_empty(&ctx->work_llist);
+ return task_work_pending(current) || !wq_list_empty(&ctx->work_llist);
}
static inline int io_run_task_work_ctx(struct io_ring_ctx *ctx)
diff --git a/io_uring/net.c b/io_uring/net.c
index 5229976cb582..fbc34a7c2743 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -494,6 +494,7 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
if (req->flags & REQ_F_BUFFER_SELECT) {
compat_ssize_t clen;
+ iomsg->free_iov = NULL;
if (msg.msg_iovlen == 0) {
sr->len = 0;
} else if (msg.msg_iovlen > 1) {
@@ -819,10 +820,10 @@ retry_multishot:
goto retry_multishot;
if (mshot_finished) {
- io_netmsg_recycle(req, issue_flags);
/* fast path, check for non-NULL to avoid function call */
if (kmsg->free_iov)
kfree(kmsg->free_iov);
+ io_netmsg_recycle(req, issue_flags);
req->flags &= ~REQ_F_NEED_CLEANUP;
}
diff --git a/io_uring/rw.c b/io_uring/rw.c
index b9cac5706e8d..8227af2e1c0f 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -1062,7 +1062,7 @@ int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
continue;
req->cqe.flags = io_put_kbuf(req, 0);
- __io_fill_cqe_req(req->ctx, req);
+ io_fill_cqe_req(req->ctx, req);
}
if (unlikely(!nr_events))
diff --git a/io_uring/timeout.c b/io_uring/timeout.c
index 5b4bc93fd6e0..826a51bca3e4 100644
--- a/io_uring/timeout.c
+++ b/io_uring/timeout.c
@@ -50,7 +50,6 @@ static inline void io_put_req(struct io_kiocb *req)
}
static bool io_kill_timeout(struct io_kiocb *req, int status)
- __must_hold(&req->ctx->completion_lock)
__must_hold(&req->ctx->timeout_lock)
{
struct io_timeout_data *io = req->async_data;
@@ -70,12 +69,13 @@ static bool io_kill_timeout(struct io_kiocb *req, int status)
}
__cold void io_flush_timeouts(struct io_ring_ctx *ctx)
- __must_hold(&ctx->completion_lock)
{
- u32 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
+ u32 seq;
struct io_timeout *timeout, *tmp;
spin_lock_irq(&ctx->timeout_lock);
+ seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
+
list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
struct io_kiocb *req = cmd_to_io_kiocb(timeout);
u32 events_needed, events_got;
@@ -622,7 +622,11 @@ __cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk,
struct io_timeout *timeout, *tmp;
int canceled = 0;
- io_cq_lock(ctx);
+ /*
+ * completion_lock is needed for io_match_task(). Take it before
+ * timeout_lockfirst to keep locking ordering.
+ */
+ spin_lock(&ctx->completion_lock);
spin_lock_irq(&ctx->timeout_lock);
list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
struct io_kiocb *req = cmd_to_io_kiocb(timeout);
@@ -632,6 +636,6 @@ __cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk,
canceled++;
}
spin_unlock_irq(&ctx->timeout_lock);
- io_cq_unlock_post(ctx);
+ spin_unlock(&ctx->completion_lock);
return canceled != 0;
}